The present invention relates to a method of and an apparatus for recovering valuables which can be recycled from waste, and specifically, a method and an apparatus which are suitable for disposing waste including circuit boards.
As to a process of recovering variables which can be recycled from waste, various technologies have been proposed in view of kinds of waste or valuables.
For example, Japanese Laid-Open Patent No. H5-147040 discloses a waste disposal method for waste of household appliance such as a refrigerator, wherein metal blocks are separated from waste, and then waste from which the metal blocks are removed, are pulverized into fragments, and then foaming materials are recovered from the fragments from which a gaseous foaming agent is recovered while iron, nonferrous metals and plastics are separated from frozen and pulverized fragments of the metal blocks and the fragments from which the foaming materials are removed, so as to recover the valuables. In order to separate iron, nonferrous metals and plastics, the fragments are subjected to magnetic separation in order to separate iron, and then the remaining fragments are subjected to eddy current separation under the action of eddy current generated by the application of a.c. magnetic fields so as to separate nonferrous metals and plastics. Further, nonferrous metals are then subjected to gravity concentration using difference in specific weight, or wind separation, so as to be sorted into copper, aluminum and other nonferrous metals, and similarly, the plastics are subjected to gravity concentration or wind separation so as to be sorted into different kinds.
Further, Japanese Laid-Open Patent No. H8-318256 proposes such a process that waste is manually disassembled so as to recover reusable parts such as CPU, and the remainder parts are pulverized and then sorted into iron, nonferrous metals and plastics in order to recover reusable parts as valuables. The remainder is further pulverized in order to recover valuables if present, and are finally subjected to innocuous disposal.
However, the waste disposal process disclosed in the Japanese Laid-Open Patent No. H5-147040 is unsatisfactory for disposing OA equipment including a circuit board. There have been offered the following matters which should be improved. That is, OA equipment such as a personal computer, a printer, a copier or a facsimile, includes a circuit board carrying thereon an electronic circuit component such as a CPU, and as well, solder which has been used for connecting electronic circuit components and wiring members, and which contains toxic lead, thereby it is desirable to enhance the recovery rate of solder. However, should OA equipment including such circuit boards be pulverized into fragments, without removing these circuit boards, the fragments would be dispersed around, solder and copper and aluminum wires being stuck thereto. Thus it is impossible to enhance the recovery rate of lead. Further, when copper, aluminum and the like of the nonferrous metal group are sorted by an eddy current classifier, eddy current is induced through solder and wiring stuck to the fragments of the circuit boards, and accordingly, a large volume of fragments of the circuit boards is recovered as nonferrous metal. As a result, a large volume of impurities relating to the circuit boards is mingled in separated nonferrous metals including copper and aluminum, and accordingly, the value of the separated nonferrous metals as valuables is lowered. Similarly, if the fragments of the circuit boards are sorted into plastics, the fragments of the circuit boards which are usually sheet-like, are likely to be sorted into phenol resin having a specific weight of 1.25 to 1.30 or polyvinyl chloride having a specific weight of 1.33 to 1.44 due to the affection by the shapes of the fragments when the fragments are sorted into different kinds of plastics since the specific weight of the circuit boards is in a range from 1.6 to 2.0, and accordingly, there would be caused a risk such that the degrees of purity of sorted plastics are lowered. Further, even after the fragments of the circuit boards are separated from nonferrous metals and other plastics, the remaining fragments are finally collected as dust together with plastic chips, metals chips, wiring chips and other particles, and accordingly, the volume of dust becomes very large so as to increase the costs of reclamation becomes high, resulting in increase in both cost of waste disposal and burden upon the environment.
In order to solve the above-mentioned problems, Japanese Patent No. H8-318256 discloses a method in which OA equipment is manually disassembled or wrecked so as to remove circuit boards, and then, valuables including CPUs are recovered as reusable parts from the circuit boars. However, it is difficult to remove circuit boards from OA equipment in view of its structure since the OA equipment is usually has a compact form. Accordingly, the removable of the circuit boards would require a huge cost and a long working time. Further, in this document, the remaining circuit boards are simply subjected to innocuous disposal for reclamation after valuables are recovered therefrom, that is, this document fails to disclose the separation and recovery of valuables such as lead contained in solder and noble metal from the circuit boards, and the reutilization thereof as resources.
Meanwhile, if a plastics housing which is one of the components of OA equipment is made of ABS resin or the like, plastics having different specific weights in a narrow range would be mingled together. That is, the specific weight of polystyrene is in the range of 1.02 to 1.51 which is substantially equal to the specific weight (1.03 to 1.09) of the ABS resin. There would be a risk such that different kinds of plastics are sorted into one and the same kind, and recovered. Accordingly, the colors and the materials of the recovered plastics are not uniform, and accordingly, the quality of the recycled resources is low.
A first object of the present invention is to enhance the quality of recovered valuables which are obtained by pulverizing waste including circuit boards, and to restrain diffusion of toxic lead included in the circuit board.
A second object of the present invention is provide an automated process for selecting and separating fragments of circuit boards from fragments of waste other than the circuit boards in order to recover valuables are recovered through the disposal of the waste including the circuit boars.
A third object of the present invention is to enhance the quality of recovered plastics, relating to colors and materials thereof.
The first object of the present invention can be achieved by such an arrangement that a circuit board sorting means for sorting and separating fragments of circuit boards from pulverized waste is provided downstream of a pulverizing means for pulverizing waste including circuit boards. That is, although it is difficult to separate fragments of circuit boards from nonferrous metals and plastics through eddy current classification or gravity concentration, with the provision of the circuit board sorting means for sorting and separating fragments of circuit boards, the amount of fragments of circuit boards mingled into nonferrous metals and plastics can be restrained. As a result, the qualities of nonferrous metals and plastics which are valuables to be recovered, can be enhanced. Further, with the provision of the circuit board sorting means, since waste including circuit boards can be directly pulverized by, for example, the pulverizing means, and accordingly, the necessity of handwork for disassembly can be eliminated, thereby it is possible to reduce the processing time for recovering circuit boards and the processing cost.
In this case, it is preferable to arrange the circuit board sorting means upstream of a nonferrous metal sorting means for sorting nonferrous metals. With this arrangement, it is possible to restrain fragments of circuit boards from being mingled into nonferrous metals. Further, since the fragments of circuit boards are separated, it is possible to apply eddy current for sorting nonferrous metals. Similarly, the circuit board sorting means is preferably provided upstream of a plastic sorting means for sorting plastics. With this arrangement, it is possible to restrain fragments of circuit boards form being mingled into plastics, and to apply gravity concentration for sorting plastics into different kinds.
Further, since fragments of circuit boards are sorted and separated, toxic lead can be separated and recovered, thereby it is possible to prevent diffusion of toxic lead. Further, noble metals contained in circuit boards can be separated and recovered. Further, since circuit boards includes, in general, glass fibers impregnated with resin, the quantity of dust to be reclaimed can be reduced by decomposing the resin so as to recover oil or the like contained therein.
A second object of the present invention is to provide a circuit board sorting means adapted to identify fragments of circuit boards in accordance with colors of circuit boards in order to solve the above-mentioned conventional problems. That is, since the color of circuit boards is, in general, green or brown, the fragments of circuit boards can be separated from other waste. Specifically, fragments are passed through the field of vision of a TV camera or a CCD camera which can therefore pick up images therefrom. Then colors of the picked-up images are compared in contrast with one or a plurality of specific colors which have been previously set in order to determine whether the fragments are those of that other than the circuit boards so as to identify fragments of circuit boards among fragments of other waste, and accordingly, the fragments of circuit boards are mechanically separated from those of other waste.
Specifically, the circuit board sorting means may be composed of an array means for arraying the fragments, being spaced from one another, in a row, and an image pick-up means such as a CCD camera for picking up images from the fragments, and an identifying means for comparing colors of images picked up from the fragments in contrast with one or a plurality of preset specified colors so as to determine whether fragments are those of the circuit boards or other waste. The array means may be composed of conveying means such as belt conveyers having a V-like sectional shape and coupled together in multiple stages in such a way that the speeds of the conveying means are higher and higher successively, and means for introducing fragments of wastes including fragments of circuit boards onto the conveying means. The circuit board identifying means may be composed of a computer or the like.
A circuit board separating means for separating fragments of circuit boards from those of other waste tracks those fragments which are sorted by the circuit board sorting means, during conveyance of arrayed fragments on a conveying path, and drops fragments of circuit boards from the conveying path at a position where the fragments of circuit boards are collected. Specifically, a ring-like fragment receiving part which is defined by an inner and an outer peripheral wall is formed on a rotatable circular table, and the outer peripheral wall is composed of several openable and closable doors which are circumferentially arranged, being adjacent to one another. The fragments discharged from the sorting means are shifted one by one onto the fragments receiving part while the circular table is rotated. Further, there is provided an image pick-up means for picking up images from the fragments having been shifted onto the fragment receiving means. The circuit board separating means determines whether a fragment is one of those of circuit boards or not in accordance with the thus picked-up image delivered from the image pick-up means. If it is a fragment of circuit boards, the position where the fragment of circuit board is located is stored in memory, in relation to the associated door. When the door comes to predetermined collecting position, a signal is delivered to a means for opening and closing the associated door in order to open the door, and accordingly, the fragment is dropped from the circular table under centrifugal force so as to separate the fragments from the other waste. It goes without saying that the above-mentioned separating means can be used for separating not only fragments of circuit boards but also those which can be identified through their picked-up images. Thus, the fragments which are conveyed on the circular table can be separated under centrifugal force, desired fragments can be separated at a high rate from a huge number of fragments of waste. That is, the method disclosed in the Japanese Laid-Open Patent No. H6-23328, using a separating device in which parts are conveyed along a predetermined conveying path by a rotary part feeder composes of a bowl and a rotatable table, then kinds of parts are determined in accordance with an image from a CCD camera, and air is blown onto these parts in order to sort the parts into different kinds and a method disclosed in the Japanese Laid-Open Patent No. H9-201572, including steps of extending a piston toward a cullet on a disc on rotation, and sucking air through a pipe line provided at the forward end of the piston so as to hold the cullet, and sorting parts into different kinds in accordance with colors with the use of images obtained by a CCD camera, would not be suitable for sorting a huge quantity of waste.
A third object of the present invention is to provide a method such that plastic parts including a housing constituting an OA equipment are wrecked, and a color and a material of the part are measured so as to sort recovered plastics into different kinds in accordance with the color and the material, in order to solve the above-mentioned problems. That is, it is possible to enhance the quality, such as a color and a material of thus recovered plastics.